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<a name="1" href="#1">1</a>   <strong class="jxr_keyword">package</strong> org.methodize.nntprss.util;
<a name="2" href="#2">2</a>   
<a name="3" href="#3">3</a>   <em class="jxr_comment">/*<em class="jxr_comment"> -----------------------------------------------------------</em></em>
<a name="4" href="#4">4</a>   <em class="jxr_comment"> * nntp//rss - a bridge between the RSS world and NNTP clients</em>
<a name="5" href="#5">5</a>   <em class="jxr_comment"> * Copyright (c) 2002-2007 Jason Brome.  All Rights Reserved.</em>
<a name="6" href="#6">6</a>   <em class="jxr_comment"> *</em>
<a name="7" href="#7">7</a>   <em class="jxr_comment"> * email: nntprss@methodize.org</em>
<a name="8" href="#8">8</a>   <em class="jxr_comment"> * mail:  Jason Brome</em>
<a name="9" href="#9">9</a>   <em class="jxr_comment"> *        PO Box 222-WOB</em>
<a name="10" href="#10">10</a>  <em class="jxr_comment"> *        West Orange</em>
<a name="11" href="#11">11</a>  <em class="jxr_comment"> *        NJ 07052-0222</em>
<a name="12" href="#12">12</a>  <em class="jxr_comment"> * </em>
<a name="13" href="#13">13</a>  <em class="jxr_comment"> * This file is part of nntp//rss</em>
<a name="14" href="#14">14</a>  <em class="jxr_comment"> * </em>
<a name="15" href="#15">15</a>  <em class="jxr_comment"> * nntp//rss is free software; you can redistribute it </em>
<a name="16" href="#16">16</a>  <em class="jxr_comment"> * and/or modify it under the terms of the GNU General </em>
<a name="17" href="#17">17</a>  <em class="jxr_comment"> * Public License as published by the Free Software Foundation; </em>
<a name="18" href="#18">18</a>  <em class="jxr_comment"> * either version 2 of the License, or (at your option) any </em>
<a name="19" href="#19">19</a>  <em class="jxr_comment"> * later version.</em>
<a name="20" href="#20">20</a>  <em class="jxr_comment"> *</em>
<a name="21" href="#21">21</a>  <em class="jxr_comment"> * This program is distributed in the hope that it will be </em>
<a name="22" href="#22">22</a>  <em class="jxr_comment"> * useful, but WITHOUT ANY WARRANTY; without even the implied </em>
<a name="23" href="#23">23</a>  <em class="jxr_comment"> * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR </em>
<a name="24" href="#24">24</a>  <em class="jxr_comment"> * PURPOSE.  See the GNU General Public License for more </em>
<a name="25" href="#25">25</a>  <em class="jxr_comment"> * details.</em>
<a name="26" href="#26">26</a>  <em class="jxr_comment"> *</em>
<a name="27" href="#27">27</a>  <em class="jxr_comment"> * You should have received a copy of the GNU General Public </em>
<a name="28" href="#28">28</a>  <em class="jxr_comment"> * License along with this program; if not, write to the </em>
<a name="29" href="#29">29</a>  <em class="jxr_comment"> * Free Software Foundation, Inc., 59 Temple Place, Suite 330, </em>
<a name="30" href="#30">30</a>  <em class="jxr_comment"> * Boston, MA  02111-1307  USA</em>
<a name="31" href="#31">31</a>  <em class="jxr_comment"> * ----------------------------------------------------- */</em>
<a name="32" href="#32">32</a>  
<a name="33" href="#33">33</a>  <em class="jxr_javadoccomment">/**</em>
<a name="34" href="#34">34</a>  <em class="jxr_javadoccomment"> * </em>
<a name="35" href="#35">35</a>  <em class="jxr_javadoccomment"> * Base64 encoding class - decoding not required for nntp//rss</em>
<a name="36" href="#36">36</a>  <em class="jxr_javadoccomment"> * </em>
<a name="37" href="#37">37</a>  <em class="jxr_javadoccomment"> * Based upon Public Domain Base64 class from Robert Harder</em>
<a name="38" href="#38">38</a>  <em class="jxr_javadoccomment"> * See: <a href="http://iharder.sourceforge.net/base64/" target="alexandria_uri">http://iharder.sourceforge.net/base64/</a></em>
<a name="39" href="#39">39</a>  <em class="jxr_javadoccomment"> * </em>
<a name="40" href="#40">40</a>  <em class="jxr_javadoccomment"> * @author Robert Harder</em>
<a name="41" href="#41">41</a>  <em class="jxr_javadoccomment"> * @author rob@iharder.net</em>
<a name="42" href="#42">42</a>  <em class="jxr_javadoccomment"> * @version 1.4</em>
<a name="43" href="#43">43</a>  <em class="jxr_javadoccomment"> */</em>
<a name="44" href="#44">44</a>  <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">class</strong> Base64 {
<a name="45" href="#45">45</a>  
<a name="46" href="#46">46</a>      <em class="jxr_javadoccomment">/**</em><em class="jxr_javadoccomment"> Specify encoding (value is &lt;tt&gt;true&lt;/tt&gt;). */</em>
<a name="47" href="#47">47</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">boolean</strong> ENCODE = <strong class="jxr_keyword">true</strong>;
<a name="48" href="#48">48</a>  
<a name="49" href="#49">49</a>      <em class="jxr_javadoccomment">/**</em><em class="jxr_javadoccomment"> Maximum line length (76) of Base64 output. */</em>
<a name="50" href="#50">50</a>      <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">int</strong> MAX_LINE_LENGTH = 76;
<a name="51" href="#51">51</a>  
<a name="52" href="#52">52</a>      <em class="jxr_javadoccomment">/**</em><em class="jxr_javadoccomment"> The equals sign (=) as a byte. */</em>
<a name="53" href="#53">53</a>      <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">static</strong> byte EQUALS_SIGN = (byte) '=';
<a name="54" href="#54">54</a>  
<a name="55" href="#55">55</a>      <em class="jxr_javadoccomment">/**</em><em class="jxr_javadoccomment"> The new line character (\n) as a byte. */</em>
<a name="56" href="#56">56</a>      <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">static</strong> byte NEW_LINE = (byte) '\n';
<a name="57" href="#57">57</a>  
<a name="58" href="#58">58</a>      <em class="jxr_javadoccomment">/**</em><em class="jxr_javadoccomment"> The 64 valid Base64 values. */</em>
<a name="59" href="#59">59</a>      <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">static</strong> byte[] ALPHABET =
<a name="60" href="#60">60</a>          {
<a name="61" href="#61">61</a>              (byte) 'A',
<a name="62" href="#62">62</a>              (byte) 'B',
<a name="63" href="#63">63</a>              (byte) 'C',
<a name="64" href="#64">64</a>              (byte) 'D',
<a name="65" href="#65">65</a>              (byte) 'E',
<a name="66" href="#66">66</a>              (byte) 'F',
<a name="67" href="#67">67</a>              (byte) 'G',
<a name="68" href="#68">68</a>              (byte) 'H',
<a name="69" href="#69">69</a>              (byte) 'I',
<a name="70" href="#70">70</a>              (byte) 'J',
<a name="71" href="#71">71</a>              (byte) 'K',
<a name="72" href="#72">72</a>              (byte) 'L',
<a name="73" href="#73">73</a>              (byte) 'M',
<a name="74" href="#74">74</a>              (byte) 'N',
<a name="75" href="#75">75</a>              (byte) 'O',
<a name="76" href="#76">76</a>              (byte) 'P',
<a name="77" href="#77">77</a>              (byte) 'Q',
<a name="78" href="#78">78</a>              (byte) 'R',
<a name="79" href="#79">79</a>              (byte) 'S',
<a name="80" href="#80">80</a>              (byte) 'T',
<a name="81" href="#81">81</a>              (byte) 'U',
<a name="82" href="#82">82</a>              (byte) 'V',
<a name="83" href="#83">83</a>              (byte) 'W',
<a name="84" href="#84">84</a>              (byte) 'X',
<a name="85" href="#85">85</a>              (byte) 'Y',
<a name="86" href="#86">86</a>              (byte) 'Z',
<a name="87" href="#87">87</a>              (byte) 'a',
<a name="88" href="#88">88</a>              (byte) 'b',
<a name="89" href="#89">89</a>              (byte) 'c',
<a name="90" href="#90">90</a>              (byte) 'd',
<a name="91" href="#91">91</a>              (byte) 'e',
<a name="92" href="#92">92</a>              (byte) 'f',
<a name="93" href="#93">93</a>              (byte) 'g',
<a name="94" href="#94">94</a>              (byte) 'h',
<a name="95" href="#95">95</a>              (byte) 'i',
<a name="96" href="#96">96</a>              (byte) 'j',
<a name="97" href="#97">97</a>              (byte) 'k',
<a name="98" href="#98">98</a>              (byte) 'l',
<a name="99" href="#99">99</a>              (byte) 'm',
<a name="100" href="#100">100</a>             (byte) 'n',
<a name="101" href="#101">101</a>             (byte) 'o',
<a name="102" href="#102">102</a>             (byte) 'p',
<a name="103" href="#103">103</a>             (byte) 'q',
<a name="104" href="#104">104</a>             (byte) 'r',
<a name="105" href="#105">105</a>             (byte) 's',
<a name="106" href="#106">106</a>             (byte) 't',
<a name="107" href="#107">107</a>             (byte) 'u',
<a name="108" href="#108">108</a>             (byte) 'v',
<a name="109" href="#109">109</a>             (byte) 'w',
<a name="110" href="#110">110</a>             (byte) 'x',
<a name="111" href="#111">111</a>             (byte) 'y',
<a name="112" href="#112">112</a>             (byte) 'z',
<a name="113" href="#113">113</a>             (byte) '0',
<a name="114" href="#114">114</a>             (byte) '1',
<a name="115" href="#115">115</a>             (byte) '2',
<a name="116" href="#116">116</a>             (byte) '3',
<a name="117" href="#117">117</a>             (byte) '4',
<a name="118" href="#118">118</a>             (byte) '5',
<a name="119" href="#119">119</a>             (byte) '6',
<a name="120" href="#120">120</a>             (byte) '7',
<a name="121" href="#121">121</a>             (byte) '8',
<a name="122" href="#122">122</a>             (byte) '9',
<a name="123" href="#123">123</a>             (byte) '+',
<a name="124" href="#124">124</a>             (byte) '/' };
<a name="125" href="#125">125</a> 
<a name="126" href="#126">126</a>     <em class="jxr_javadoccomment">/**</em><em class="jxr_javadoccomment"> </em>
<a name="127" href="#127">127</a> <em class="jxr_javadoccomment">     * Translates a Base64 value to either its 6-bit reconstruction value</em>
<a name="128" href="#128">128</a> <em class="jxr_javadoccomment">     * or a negative number indicating some other meaning.</em>
<a name="129" href="#129">129</a> <em class="jxr_javadoccomment">     **/</em>
<a name="130" href="#130">130</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">static</strong> byte[] DECODABET =
<a name="131" href="#131">131</a>         { -9, -9, -9, -9, -9, -9, -9, -9, -9, <em class="jxr_comment">// Decimal  0 -  8</em>
<a name="132" href="#132">132</a>         -5, -5, <em class="jxr_comment">// Whitespace: Tab and Linefeed</em>
<a name="133" href="#133">133</a>         -9, -9, <em class="jxr_comment">// Decimal 11 - 12</em>
<a name="134" href="#134">134</a>         -5, <em class="jxr_comment">// Whitespace: Carriage Return</em>
<a name="135" href="#135">135</a>         -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, <em class="jxr_comment">// Decimal 14 - 26</em>
<a name="136" href="#136">136</a>         -9, -9, -9, -9, -9, <em class="jxr_comment">// Decimal 27 - 31</em>
<a name="137" href="#137">137</a>         -5, <em class="jxr_comment">// Whitespace: Space</em>
<a name="138" href="#138">138</a>         -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, <em class="jxr_comment">// Decimal 33 - 42</em>
<a name="139" href="#139">139</a>         62, <em class="jxr_comment">// Plus sign at decimal 43</em>
<a name="140" href="#140">140</a>         -9, -9, -9, <em class="jxr_comment">// Decimal 44 - 46</em>
<a name="141" href="#141">141</a>         63, <em class="jxr_comment">// Slash at decimal 47</em>
<a name="142" href="#142">142</a>         52, 53, 54, 55, 56, 57, 58, 59, 60, 61, <em class="jxr_comment">// Numbers zero through nine</em>
<a name="143" href="#143">143</a>         -9, -9, -9, <em class="jxr_comment">// Decimal 58 - 60</em>
<a name="144" href="#144">144</a>         -1, <em class="jxr_comment">// Equals sign at decimal 61</em>
<a name="145" href="#145">145</a>         -9, -9, -9, <em class="jxr_comment">// Decimal 62 - 64</em>
<a name="146" href="#146">146</a>         0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
<a name="147" href="#147">147</a>         <em class="jxr_comment">// Letters 'A' through 'N'</em>
<a name="148" href="#148">148</a>         14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
<a name="149" href="#149">149</a>         <em class="jxr_comment">// Letters 'O' through 'Z'</em>
<a name="150" href="#150">150</a>         -9, -9, -9, -9, -9, -9, <em class="jxr_comment">// Decimal 91 - 96</em>
<a name="151" href="#151">151</a>         26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
<a name="152" href="#152">152</a>         <em class="jxr_comment">// Letters 'a' through 'm'</em>
<a name="153" href="#153">153</a>         39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,
<a name="154" href="#154">154</a>         <em class="jxr_comment">// Letters 'n' through 'z'</em>
<a name="155" href="#155">155</a>         -9, -9, -9, -9 <em class="jxr_comment">// Decimal 123 - 126</em>
<a name="156" href="#156">156</a>         <em class="jxr_comment">/*<em class="jxr_comment">,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 127 - 139</em></em>
<a name="157" href="#157">157</a> <em class="jxr_comment">        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 140 - 152</em>
<a name="158" href="#158">158</a> <em class="jxr_comment">        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 153 - 165</em>
<a name="159" href="#159">159</a> <em class="jxr_comment">        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 166 - 178</em>
<a name="160" href="#160">160</a> <em class="jxr_comment">        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 179 - 191</em>
<a name="161" href="#161">161</a> <em class="jxr_comment">        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 192 - 204</em>
<a name="162" href="#162">162</a> <em class="jxr_comment">        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 205 - 217</em>
<a name="163" href="#163">163</a> <em class="jxr_comment">        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 218 - 230</em>
<a name="164" href="#164">164</a> <em class="jxr_comment">        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 231 - 243</em>
<a name="165" href="#165">165</a> <em class="jxr_comment">        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9         // Decimal 244 - 255 */</em>
<a name="166" href="#166">166</a>     };
<a name="167" href="#167">167</a> 
<a name="168" href="#168">168</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">static</strong> byte BAD_ENCODING = -9; <em class="jxr_comment">// Indicates error in encoding</em>
<a name="169" href="#169">169</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">static</strong> byte WHITE_SPACE_ENC = -5;
<a name="170" href="#170">170</a>     <em class="jxr_comment">// Indicates white space in encoding</em>
<a name="171" href="#171">171</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">static</strong> byte EQUALS_SIGN_ENC = -1;
<a name="172" href="#172">172</a>     <em class="jxr_comment">// Indicates equals sign in encoding</em>
<a name="173" href="#173">173</a> 
<a name="174" href="#174">174</a>     <em class="jxr_javadoccomment">/**</em><em class="jxr_javadoccomment"> Defeats instantiation. */</em>
<a name="175" href="#175">175</a>     <strong class="jxr_keyword">private</strong> Base64() {
<a name="176" href="#176">176</a>     }
<a name="177" href="#177">177</a> 
<a name="178" href="#178">178</a>     <em class="jxr_comment">/*<em class="jxr_comment"> ********  E N C O D I N G   M E T H O D S  ******** */</em></em>
<a name="179" href="#179">179</a> 
<a name="180" href="#180">180</a>     <em class="jxr_javadoccomment">/**</em>
<a name="181" href="#181">181</a> <em class="jxr_javadoccomment">     * Encodes the first three bytes of array &lt;var&gt;threeBytes&lt;/var&gt;</em>
<a name="182" href="#182">182</a> <em class="jxr_javadoccomment">     * and returns a four-byte array in Base64 notation.</em>
<a name="183" href="#183">183</a> <em class="jxr_javadoccomment">     *</em>
<a name="184" href="#184">184</a> <em class="jxr_javadoccomment">     * @param threeBytes the array to convert</em>
<a name="185" href="#185">185</a> <em class="jxr_javadoccomment">     * @return four byte array in Base64 notation.</em>
<a name="186" href="#186">186</a> <em class="jxr_javadoccomment">     * @since 1.3</em>
<a name="187" href="#187">187</a> <em class="jxr_javadoccomment">     */</em>
<a name="188" href="#188">188</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> byte[] encode3to4(byte[] threeBytes) {
<a name="189" href="#189">189</a>         <strong class="jxr_keyword">return</strong> encode3to4(threeBytes, 3);
<a name="190" href="#190">190</a>     } <em class="jxr_comment">// end encodeToBytes</em>
<a name="191" href="#191">191</a> 
<a name="192" href="#192">192</a>     <em class="jxr_javadoccomment">/**</em>
<a name="193" href="#193">193</a> <em class="jxr_javadoccomment">     * Encodes up to the first three bytes of array &lt;var&gt;threeBytes&lt;/var&gt;</em>
<a name="194" href="#194">194</a> <em class="jxr_javadoccomment">     * and returns a four-byte array in Base64 notation.</em>
<a name="195" href="#195">195</a> <em class="jxr_javadoccomment">     * The actual number of significant bytes in your array is</em>
<a name="196" href="#196">196</a> <em class="jxr_javadoccomment">     * given by &lt;var&gt;numSigBytes&lt;/var&gt;.</em>
<a name="197" href="#197">197</a> <em class="jxr_javadoccomment">     * The array &lt;var&gt;threeBytes&lt;/var&gt; needs only be as big as</em>
<a name="198" href="#198">198</a> <em class="jxr_javadoccomment">     * &lt;var&gt;numSigBytes&lt;/var&gt;.</em>
<a name="199" href="#199">199</a> <em class="jxr_javadoccomment">     *</em>
<a name="200" href="#200">200</a> <em class="jxr_javadoccomment">     * @param threeBytes the array to convert</em>
<a name="201" href="#201">201</a> <em class="jxr_javadoccomment">     * @param numSigBytes the number of significant bytes in your array</em>
<a name="202" href="#202">202</a> <em class="jxr_javadoccomment">     * @return four byte array in Base64 notation.</em>
<a name="203" href="#203">203</a> <em class="jxr_javadoccomment">     * @since 1.3</em>
<a name="204" href="#204">204</a> <em class="jxr_javadoccomment">     */</em>
<a name="205" href="#205">205</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> byte[] encode3to4(byte[] threeBytes, <strong class="jxr_keyword">int</strong> numSigBytes) {
<a name="206" href="#206">206</a>         byte[] dest = <strong class="jxr_keyword">new</strong> byte[4];
<a name="207" href="#207">207</a>         encode3to4(threeBytes, 0, numSigBytes, dest, 0);
<a name="208" href="#208">208</a>         <strong class="jxr_keyword">return</strong> dest;
<a name="209" href="#209">209</a>     }
<a name="210" href="#210">210</a> 
<a name="211" href="#211">211</a>     <em class="jxr_javadoccomment">/**</em>
<a name="212" href="#212">212</a> <em class="jxr_javadoccomment">     * Encodes up to three bytes of the array &lt;var&gt;source&lt;/var&gt;</em>
<a name="213" href="#213">213</a> <em class="jxr_javadoccomment">     * and writes the resulting four Base64 bytes to &lt;var&gt;destination&lt;/var&gt;.</em>
<a name="214" href="#214">214</a> <em class="jxr_javadoccomment">     * The source and destination arrays can be manipulated</em>
<a name="215" href="#215">215</a> <em class="jxr_javadoccomment">     * anywhere along their length by specifying </em>
<a name="216" href="#216">216</a> <em class="jxr_javadoccomment">     * &lt;var&gt;srcOffset&lt;/var&gt; and &lt;var&gt;destOffset&lt;/var&gt;.</em>
<a name="217" href="#217">217</a> <em class="jxr_javadoccomment">     * This method does not check to make sure your arrays</em>
<a name="218" href="#218">218</a> <em class="jxr_javadoccomment">     * are large enough to accomodate &lt;var&gt;srcOffset&lt;/var&gt; + 3 for</em>
<a name="219" href="#219">219</a> <em class="jxr_javadoccomment">     * the &lt;var&gt;source&lt;/var&gt; array or &lt;var&gt;destOffset&lt;/var&gt; + 4 for</em>
<a name="220" href="#220">220</a> <em class="jxr_javadoccomment">     * the &lt;var&gt;destination&lt;/var&gt; array.</em>
<a name="221" href="#221">221</a> <em class="jxr_javadoccomment">     * The actual number of significant bytes in your array is</em>
<a name="222" href="#222">222</a> <em class="jxr_javadoccomment">     * given by &lt;var&gt;numSigBytes&lt;/var&gt;.</em>
<a name="223" href="#223">223</a> <em class="jxr_javadoccomment">     *</em>
<a name="224" href="#224">224</a> <em class="jxr_javadoccomment">     * @param source the array to convert</em>
<a name="225" href="#225">225</a> <em class="jxr_javadoccomment">     * @param srcOffset the index where conversion begins</em>
<a name="226" href="#226">226</a> <em class="jxr_javadoccomment">     * @param numSigBytes the number of significant bytes in your array</em>
<a name="227" href="#227">227</a> <em class="jxr_javadoccomment">     * @param destination the array to hold the conversion</em>
<a name="228" href="#228">228</a> <em class="jxr_javadoccomment">     * @param destOffset the index where output will be put</em>
<a name="229" href="#229">229</a> <em class="jxr_javadoccomment">     * @return the &lt;var&gt;destination&lt;/var&gt; array</em>
<a name="230" href="#230">230</a> <em class="jxr_javadoccomment">     * @since 1.3</em>
<a name="231" href="#231">231</a> <em class="jxr_javadoccomment">     */</em>
<a name="232" href="#232">232</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> byte[] encode3to4(
<a name="233" href="#233">233</a>         byte[] source,
<a name="234" href="#234">234</a>         <strong class="jxr_keyword">int</strong> srcOffset,
<a name="235" href="#235">235</a>         <strong class="jxr_keyword">int</strong> numSigBytes,
<a name="236" href="#236">236</a>         byte[] destination,
<a name="237" href="#237">237</a>         <strong class="jxr_keyword">int</strong> destOffset) {
<a name="238" href="#238">238</a>         <em class="jxr_comment">//           1         2         3  </em>
<a name="239" href="#239">239</a>         <em class="jxr_comment">// 01234567890123456789012345678901 Bit position</em>
<a name="240" href="#240">240</a>         <em class="jxr_comment">// --------000000001111111122222222 Array position from threeBytes</em>
<a name="241" href="#241">241</a>         <em class="jxr_comment">// --------|    ||    ||    ||    | Six bit groups to index ALPHABET</em>
<a name="242" href="#242">242</a>         <em class="jxr_comment">//          &gt;&gt;18  &gt;&gt;12  &gt;&gt; 6  &gt;&gt; 0  Right shift necessary</em>
<a name="243" href="#243">243</a>         <em class="jxr_comment">//                0x3f  0x3f  0x3f  Additional AND</em>
<a name="244" href="#244">244</a> 
<a name="245" href="#245">245</a>         <em class="jxr_comment">// Create buffer with zero-padding if there are only one or two</em>
<a name="246" href="#246">246</a>         <em class="jxr_comment">// significant bytes passed in the array.</em>
<a name="247" href="#247">247</a>         <em class="jxr_comment">// We have to shift left 24 in order to flush out the 1's that appear</em>
<a name="248" href="#248">248</a>         <em class="jxr_comment">// when Java treats a value as negative that is cast from a byte to an int.</em>
<a name="249" href="#249">249</a>         <strong class="jxr_keyword">int</strong> inBuff =
<a name="250" href="#250">250</a>             (numSigBytes &gt; 0 ? ((source[srcOffset] &lt;&lt; 24) &gt;&gt;&gt; 8) : 0)
<a name="251" href="#251">251</a>                 | (numSigBytes &gt; 1 ? ((source[srcOffset + 1] &lt;&lt; 24) &gt;&gt;&gt; 16) : 0)
<a name="252" href="#252">252</a>                 | (numSigBytes &gt; 2 ? ((source[srcOffset + 2] &lt;&lt; 24) &gt;&gt;&gt; 24) : 0);
<a name="253" href="#253">253</a> 
<a name="254" href="#254">254</a>         <strong class="jxr_keyword">switch</strong> (numSigBytes) {
<a name="255" href="#255">255</a>             <strong class="jxr_keyword">case</strong> 3 :
<a name="256" href="#256">256</a>                 destination[destOffset] = ALPHABET[(inBuff &gt;&gt;&gt; 18)];
<a name="257" href="#257">257</a>                 destination[destOffset + 1] = ALPHABET[(inBuff &gt;&gt;&gt; 12) &amp; 0x3f];
<a name="258" href="#258">258</a>                 destination[destOffset + 2] = ALPHABET[(inBuff &gt;&gt;&gt; 6) &amp; 0x3f];
<a name="259" href="#259">259</a>                 destination[destOffset + 3] = ALPHABET[(inBuff) &amp; 0x3f];
<a name="260" href="#260">260</a>                 <strong class="jxr_keyword">return</strong> destination;
<a name="261" href="#261">261</a> 
<a name="262" href="#262">262</a>             <strong class="jxr_keyword">case</strong> 2 :
<a name="263" href="#263">263</a>                 destination[destOffset] = ALPHABET[(inBuff &gt;&gt;&gt; 18)];
<a name="264" href="#264">264</a>                 destination[destOffset + 1] = ALPHABET[(inBuff &gt;&gt;&gt; 12) &amp; 0x3f];
<a name="265" href="#265">265</a>                 destination[destOffset + 2] = ALPHABET[(inBuff &gt;&gt;&gt; 6) &amp; 0x3f];
<a name="266" href="#266">266</a>                 destination[destOffset + 3] = EQUALS_SIGN;
<a name="267" href="#267">267</a>                 <strong class="jxr_keyword">return</strong> destination;
<a name="268" href="#268">268</a> 
<a name="269" href="#269">269</a>             <strong class="jxr_keyword">case</strong> 1 :
<a name="270" href="#270">270</a>                 destination[destOffset] = ALPHABET[(inBuff &gt;&gt;&gt; 18)];
<a name="271" href="#271">271</a>                 destination[destOffset + 1] = ALPHABET[(inBuff &gt;&gt;&gt; 12) &amp; 0x3f];
<a name="272" href="#272">272</a>                 destination[destOffset + 2] = EQUALS_SIGN;
<a name="273" href="#273">273</a>                 destination[destOffset + 3] = EQUALS_SIGN;
<a name="274" href="#274">274</a>                 <strong class="jxr_keyword">return</strong> destination;
<a name="275" href="#275">275</a> 
<a name="276" href="#276">276</a>             <strong class="jxr_keyword">default</strong> :
<a name="277" href="#277">277</a>                 <strong class="jxr_keyword">return</strong> destination;
<a name="278" href="#278">278</a>         } <em class="jxr_comment">// end switch</em>
<a name="279" href="#279">279</a>     } <em class="jxr_comment">// end encode3to4</em>
<a name="280" href="#280">280</a> 
<a name="281" href="#281">281</a>     <em class="jxr_javadoccomment">/**</em>
<a name="282" href="#282">282</a> <em class="jxr_javadoccomment">     * Encodes a byte array into Base64 notation.</em>
<a name="283" href="#283">283</a> <em class="jxr_javadoccomment">     * Equivalen to calling</em>
<a name="284" href="#284">284</a> <em class="jxr_javadoccomment">     * &lt;code&gt;encodeBytes( source, 0, source.length )&lt;/code&gt;</em>
<a name="285" href="#285">285</a> <em class="jxr_javadoccomment">     *</em>
<a name="286" href="#286">286</a> <em class="jxr_javadoccomment">     * @param source The data to convert</em>
<a name="287" href="#287">287</a> <em class="jxr_javadoccomment">     * @since 1.4</em>
<a name="288" href="#288">288</a> <em class="jxr_javadoccomment">     */</em>
<a name="289" href="#289">289</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> String encodeBytes(byte[] source) {
<a name="290" href="#290">290</a>         <strong class="jxr_keyword">return</strong> encodeBytes(source, <strong class="jxr_keyword">true</strong>);
<a name="291" href="#291">291</a>     } <em class="jxr_comment">// end encodeBytes</em>
<a name="292" href="#292">292</a> 
<a name="293" href="#293">293</a>     <em class="jxr_javadoccomment">/**</em>
<a name="294" href="#294">294</a> <em class="jxr_javadoccomment">     * Encodes a byte array into Base64 notation.</em>
<a name="295" href="#295">295</a> <em class="jxr_javadoccomment">     * Equivalen to calling</em>
<a name="296" href="#296">296</a> <em class="jxr_javadoccomment">     * &lt;code&gt;encodeBytes( source, 0, source.length )&lt;/code&gt;</em>
<a name="297" href="#297">297</a> <em class="jxr_javadoccomment">     *</em>
<a name="298" href="#298">298</a> <em class="jxr_javadoccomment">     * @param source The data to convert</em>
<a name="299" href="#299">299</a> <em class="jxr_javadoccomment">     * @param breakLines Break lines at 80 characters or less.</em>
<a name="300" href="#300">300</a> <em class="jxr_javadoccomment">     * @since 1.4</em>
<a name="301" href="#301">301</a> <em class="jxr_javadoccomment">     */</em>
<a name="302" href="#302">302</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> String encodeBytes(byte[] source, <strong class="jxr_keyword">boolean</strong> breakLines) {
<a name="303" href="#303">303</a>         <strong class="jxr_keyword">return</strong> encodeBytes(source, 0, source.length, breakLines);
<a name="304" href="#304">304</a>     } <em class="jxr_comment">// end encodeBytes</em>
<a name="305" href="#305">305</a> 
<a name="306" href="#306">306</a>     <em class="jxr_javadoccomment">/**</em>
<a name="307" href="#307">307</a> <em class="jxr_javadoccomment">     * Encodes a byte array into Base64 notation.</em>
<a name="308" href="#308">308</a> <em class="jxr_javadoccomment">     *</em>
<a name="309" href="#309">309</a> <em class="jxr_javadoccomment">     * @param source The data to convert</em>
<a name="310" href="#310">310</a> <em class="jxr_javadoccomment">     * @param off Offset in array where conversion should begin</em>
<a name="311" href="#311">311</a> <em class="jxr_javadoccomment">     * @param len Length of data to convert</em>
<a name="312" href="#312">312</a> <em class="jxr_javadoccomment">     * @param breakLines Break lines at 80 characters or less.</em>
<a name="313" href="#313">313</a> <em class="jxr_javadoccomment">     * @since 1.4</em>
<a name="314" href="#314">314</a> <em class="jxr_javadoccomment">     */</em>
<a name="315" href="#315">315</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> String encodeBytes(
<a name="316" href="#316">316</a>         byte[] source,
<a name="317" href="#317">317</a>         <strong class="jxr_keyword">int</strong> off,
<a name="318" href="#318">318</a>         <strong class="jxr_keyword">int</strong> len,
<a name="319" href="#319">319</a>         <strong class="jxr_keyword">boolean</strong> breakLines) {
<a name="320" href="#320">320</a>         <strong class="jxr_keyword">int</strong> len43 = len * 4 / 3;
<a name="321" href="#321">321</a>             byte[] outBuff = <strong class="jxr_keyword">new</strong> byte[(len43) <em class="jxr_comment">// Main 4:3</em>
<a name="322" href="#322">322</a>         + ((len % 3) &gt; 0 ? 4 : 0) <em class="jxr_comment">// Account for padding</em>
<a name="323" href="#323">323</a>     + (breakLines ? (len43 / MAX_LINE_LENGTH) : 0)]; <em class="jxr_comment">// New lines      </em>
<a name="324" href="#324">324</a>         <strong class="jxr_keyword">int</strong> d = 0;
<a name="325" href="#325">325</a>         <strong class="jxr_keyword">int</strong> e = 0;
<a name="326" href="#326">326</a>         <strong class="jxr_keyword">int</strong> len2 = len - 2;
<a name="327" href="#327">327</a>         <strong class="jxr_keyword">int</strong> lineLength = 0;
<a name="328" href="#328">328</a>         <strong class="jxr_keyword">for</strong> (; d &lt; len2; d += 3, e += 4) {
<a name="329" href="#329">329</a>             encode3to4(source, d + off, 3, outBuff, e);
<a name="330" href="#330">330</a> 
<a name="331" href="#331">331</a>             lineLength += 4;
<a name="332" href="#332">332</a>             <strong class="jxr_keyword">if</strong> (breakLines &amp;&amp; lineLength == MAX_LINE_LENGTH) {
<a name="333" href="#333">333</a>                 outBuff[e + 4] = NEW_LINE;
<a name="334" href="#334">334</a>                 e++;
<a name="335" href="#335">335</a>                 lineLength = 0;
<a name="336" href="#336">336</a>             } <em class="jxr_comment">// end if: end of line</em>
<a name="337" href="#337">337</a>         } <em class="jxr_comment">// en dfor: each piece of array</em>
<a name="338" href="#338">338</a> 
<a name="339" href="#339">339</a>         <strong class="jxr_keyword">if</strong> (d &lt; len) {
<a name="340" href="#340">340</a>             encode3to4(source, d + off, len - d, outBuff, e);
<a name="341" href="#341">341</a>             e += 4;
<a name="342" href="#342">342</a>         } <em class="jxr_comment">// end if: some padding needed</em>
<a name="343" href="#343">343</a> 
<a name="344" href="#344">344</a>         <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">new</strong> String(outBuff, 0, e);
<a name="345" href="#345">345</a>     } <em class="jxr_comment">// end encodeBytes</em>
<a name="346" href="#346">346</a> 
<a name="347" href="#347">347</a> } <em class="jxr_comment">// end class Base64</em>
</pre>
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